le prieur



Nov. 29, 1927. 1,651,093

Y P. G. LE PRIEUR SIGHT FOR MACHINE GUNS FOR ANTIAIRCRAFT FIRING Filed May 4. 1926 5 Sheets-Sheet l Mvhkar VP 6. L6 r/eur M W Nov. 29, 1927. 1,651,093

Y. P. G. LE PRIEUR SIGHT FOR MACHINE GUNS FOR ANTIAIRCRAFT FIRING Filed May 4. 1926 5 Sheets-Sheet 2 /n vanfiar YQG: [e prvleur Nov. 29, 1927. 1,651,093

- Y. P. G. LE PRIEUR SIGHT FOR MACHINE GUNS FOR ANTIAIRCRAFT FIRING Filed May 4, 1926 5 Sheets-Sheet 3 /n Men 5 0 r- Nov. 29, 1927.

Y. P. G. LE PRIEUR SIGHT FOR MACHINE GUNS FOR ANTIAIRCRAFT FIRING 5 Sheets-Sheet 4 /r) i/enf'ol We. 46 jar/6w" Nov. 29, 192 7. 1,651,093

Y. P. G. LE PRIEUR SIGHT FOR MACHINE GUNS FOR ANTIAIRCRAFT FIRING Filed May 4, 1926 5 Sheets-Sheet 5 4 6. 4e Pawn Patented Nov. 29, 1927.

UNITED STATES PATENT OFFICE Y VES PAUL GASTON LE PRIEUR, OF FARIS, FRANCE, ASSIGNOR TO SOCIETE ANONYME LA PRECISION MODERNE, OF PARIS, FRANCE.

SIGHT FOR MACHINE GUNS FOR ANTIAIRCRAFT FIRING.

Application filed May 4, 1926, Serial No. 106,703 and in France May 16, 1925.

The back sight correction (Fig. 1) is calculated by the well-known vertica'l back-sight ,method. Suppose ab is the barrel of a firearm levelled at a target disposed in the horizontal plane (site zero). The line of sight passes through a sight b disposed in front of-thevertical line ac. If it is desired to fire at a target disposed at the same distance as'the first target considered but at a point thefangle, of site of which is s. it can easily be-calculated and experience shows that it issuliicient. to rotate the fire arm round 8 in orderto bring its end in 6' without changing the back sight as, provided this back sight remains vertical.

r; The mechanical apparatus according to my invention .Which embody these principles are especially intended for use with portable fire arrnsisuch as -machine guns. They must thereforqshqw at the same time the maxisimplieityand ease in handling as well as the maximum-strength and also require the minimum-effort from the gunners. They are constituted by. a. cylindrical casing kept constantly vertical and wherein is disposed .a ,cylindrical.box which can rotate inside the said casing. Thecylindrical box is traversed by-a vertical. rod which can move along a radius of the box. while remaining parallel ..to its .original position. .sThis rod is pivotally secured at. one of its ends; to any arm or a "directing shaft pivotally secured to a. hori- .zonta-l shaft secured to the box, the said arm -or directingshaft, being disposed parallel to .the ..path..fo'llowed by the aircraft. At its other extremity. the aforementioned. rod .is pivotedto another rod bearing the aiming device and connected with a part of the firearm.

The. cylindrical casing can be secured to am firearm after the manner of a pendulum and the verticality of its axis can be provided by an arrangment comprising an articulated parallelogram secured to the support of the fire-arm. Inthe apparatus according to the present invention the directing shaft can be directed parallel to the path followed by the aircraft Whether this path is horizontal or not. But when the path is not horizontal, if for instance the aircraft moves downward its speed increases; if it rises on the contrary its speed diminishes. An important feature of the den M. I, vices built according to my present invention consist? in that suitable speed correction is automatically introduced when the directing shaft is rotated round its horizontal pivot. I

In view of this, several arrangements have been devised which embody the following principle: a controlling part actuates directly a carriage the movement of which depends on the speed, whereas the socket which the vertical rod passing through the box enga es, is secured to another carriage slida bly mounted on the first carriage. This second carriage is adapted to be movedalong-with the first one when the cont-rollingpart is actuated, but it can also be moved independently .with reference to the said-firstcarriage; this independent moveinentfbeing caused when the-,directing shaft is directed parallel to the inclined pathfolltiwedby. the aircraft. 1

Several forms of execution of asiglit line according to my invention are shownl by .way of example on appended. drawings whereof: v Figs. 1 and 2 deseribedhereinabove disclose the principle of the apparatus.

Figs. 3 to 10 relate to a first form of execiition of an apparatus. 1 i

Fig. 3 is a general perspective .view thereof.

Fig.4:is a plan view. Fig. 5 is a detail sectional'view. through the cylindrical box. 1 Fig. 6 is a. detai'lfofFiggb showiii gthe' -arrangementfof the two carriages -sIidii-bly secured together, the onter carriage having been. cut so as to allow theworking offthe arrangement to befreadily iinderstood.; Fig 7 is asectional view..similar. to.:Fig. f a modified form of the.apparatu s., Fig. 8 is a detailsectional viewlofth e modified .form perpendicular to the section shown by Fig, 7. i

Fig. 9 is a section similar to thosef o f Figs. 5 and T of another modifiediformof-executionand Fig. 10 is a detail section p'erpendicular to Fig.9 of this last modified Figs. 11 to 13 relate to the second form of execution embodying the formula Fig. 11 is a general outer view thereof. Fig. 12 is an explanatory diagramand, Fig. 13 shows the detail of thediiferent members of the sight line'and of the calculating box. v 7

'Re e-lill'lg to Fig. 1 is the machine gun around which set the support Q which the slides?) secured to a block 4 is adapted to move parallel to the axis of the machine gun. A circular limb 5 (Fig. 5) is cast with the support 2 and serves to guide and to hold securely the cylindrical casing 6 which hangs after the manner of a pendulum. 1n order tokeep the axis of the cylindrical casing constantly vertical, the latter is provided with lug 7 pivotaliy secured to the connecting rod 8. The said connecting rod is on the other hand pivotally secured at a stationary point 9 to the support 10 of the machine-gun." Thus an articulated parallelogram is "obtained the four apices of which'are the tnunnion 11 of the machine disposed'the cylindrical'box 12 which can be raise'di'on loweredwith reference to the castag 6 and'rot'ate' with reference thereto. The crank 13 disposed on the support 2 allows simultaneously the slider 3 to be moved with a reference to'the support 2 and the box 12 to b e raised'or lowered with reference to the casing 5. T0,t-he .b0x 12 is secured the' socket 14 wherein the arm or directing shaft 16 is adapted to'r'otate roundthe horizontal axls' l5 so as to be directed parallel to the path followed by the aircraft. 'To this shaft ispiv'otally secured the'rod'li'which passes through the box 12 and bears at its. toppart a socket 18 supporting ,a swivel joint. 19

which connect: the'rod' 17 with the rod 20.

This latter rod passes through a sleeve 21 hearing a luminous collimatorf22'such as the Chretien collimator. The sleeve 21 is pivota'lly secured totbe block i whereby it is adapted to move accordin to the movements of this block. I The rod 17 can move parallel to its axis in the elongated slot 23 directed along a radius of the box 12. This motion is controlled by the knob 24.

The whole ofthe sight 'line having been thus briefly described I will now proceed to describe more in detail each of its parts and their manner of working,

Figs. 4 and 5 are explanatory diagrams which show how the box 12 is made to be raised and lowered with reference to the casing 6. v The crank 13 provides for the rotation of a pinion 26 meshing with two racks 27, disposed at right angles one with reference to the other. The rack 28 ends with a projection actuating a lever 29 on the pivoting axis of which is keyed a toothed sector 30 meshing with the toothed ring 31 which is thus caused to rotate. This ring 31 is provided with an inner helical rack having'a coarze pitch meshin with a corresponding toothwork provided on the sleeve which can rotate round the box 12 but cannot move verticall with reference thereto. tion of the ring 31 causes the box 12 to be raised or lowered and consequently as the box 12 is secured to the socket 14, the shaft 16 and the rod 17, also causes the latter to be raised or lowered and consequently the back sight to be suitably moved.

The Figures 5' and 6 allow the manner of taking into account the variations of speed to be understood.

The rod 17 passes through a sleeve 34secured to a carriage 35 inside which another carriage 36' is adapted 'to slide. This'carriage 36is jprovided with a camshapedaperture 37. he carriage 36 passes througha longitudinal slot' provided in the' rp'd -"'17. This rod shows a' cotter 38 whic'h' passes through the"carri age 36 and engagesthe aperture 37'. Besides the inuer carria ge36 shows two stops 39*between which is disposed an eccentric 40 the rotation of which is controlled by the knob'24; 'It"-i's' easy to understand which are the relative 'r'novements oft-hese several parts. In view-of taking into account'the, speed, the knob 24 is rotated whereby the rotation of the eccentric 40 makes the inner carriage 36 move longitudinally. Latter 'carriage' bymeans of the cotter 38 draws along with it the rod 17 and thereby the outer carriage 35. The whole arrangement 'nioves inside the, elongated slot 23. The knob 41 ofthe lower end offthe rod 17 moves in the elongated slot 42.

Vihen the aircraft, serving'as a target moves downwards or upwards the gunner who actuates 'the directing shaft 16 must give it a certain incline. Let 'us suppose for instance he lowers it whereby he provides for the lowering of the rod 17. This latter rod is compelled to follow the longitudinal slot 37 during its downward movement because the carriage 35 remains stationary. Consequently the rod 17 and therewith the outer carriage 35 moves from left to right; The speed value is increased by a given quantity by the profile given to the cam shaped aperture 37. It can be seen that, in the case of an aircraft which moves downwards, the mere inclination of the haft 16 provides for the automatic addition to the speed marked of a correction corresponding to the increase of the speed for a descending aircraft. If the aircraft ascends, the reverse movements are. of course, provided.

Obviously the relative movement of the two carriages (inner and outer carriages) can he obtained by a great number of other mechanical equivalents.

Thus in the form of execution shown on Figs. 7 and 8 the inner carriage 45 directly controlled by the eccentric 46 shows Thus it is eviden' that the rotallo notch '47 which can be engaged by the bell crank 48 the axis 49 of which is pivotally secured t the walls 50 constituting the-outer carriage. The ot-her end of the lever48 appears as a ball 50 inserted in a recess 51 provided in the rod 52 correspondingto rod 17 on Fig. 5.

It may be readily understood that if the knob 53' is actuated the carriage will be moved and thereby the bell crank 48-which ,do'es-not rotate 'makes the outer carria e and consequently the rod 52 move. I

round'iits axis-49: but as it bears against. the notch 47=of the carriage 45 which re- T'Ih'ainsstationary the axis 49 is made to move from" righ'tto' left or from left to right.

T i axis lr9draws along with it the outer carria e- 550 "and therewith th d 52 The 'reqnired' correctionis thus automatically intr'odi'iced j Itflshould be noted that in both above described 'for'rns of execution, it is generally thehahd'lingf-the'apparatus, to limit the '75:? fscale of speeds of the target to two values 'tions corresponding tothe'se speeds.

'63 rotates round its pivot.

only-9 Tlius the-tWO yaIuesof 200 and 300 per hour can be chosen. Under such conditions 7 stop devices are provided which make the 'knob's'be set in the two exact posi- These stop'" devices can be constituted for instance as showr'iyonFigs. 5" and 7 by'a ball 56 enter one or the"'other ofth'e recesses 58,

'59 '(Fig.'-4)providedon the surface of the 'a'toothed sector 62 secured to the shaft 63 and-moving consequently when the shaft I Inside the car riage 'is provided a'perforation 64. through which passes the sleeve 65 provided with an eccentricbore 66 through which passes the rod" 67. The sleeve 65 is provided with a knob'68 which'can be given only two positions. It can be seen thatif the knob 68 is rotated and given oneof these two positions, the rod 67will be given the position corresponding to one of the standard speeds clioseni'i On the other hand when the shaft 63 is raised or lowered,v thecarriage 60 is actuated by means of the sector 62 and the rack 61 and thereby the correction due to the upward or downward movement of the aircraft is automatically made.

As explained hereinh'efore with reference to Fig. 2, the second form of execution of the apparatus a general view of which is given on Fig. 11 provides for a constant length 'Oe equal to one. -Therefore the block .70

wherein the rod 71 is adapted to slide is stationary with'r'eference-to the fire-arm instead of moving along latter as in the first form of execution described with reference to Figs. 3 to 10 proportionately to'the-distance. The apparatus comprises as in the first case; a cylindrical casing '72 containing with reference thereto The raising movement is produced by means of the toothed ring-74'controlled by a worm '75 secured to a rod 76. actuated by a milled knob .77. On the other hand the directing shaft serves like in the beforedescribed :apparatus for .controlling the position'ofathe -inner carriage.

' The movement of the *verticalrod 79 along a radius of the box is"pr'oduced by the inner carriage 82 the upward and .downward movements of which-are'controlled by the toothed firing :83 outwardly controlled by the rack'84 to which'aregivemthe' lon- D The carriage82 controls the rod 79 byme'ans of the inner toothwork of 82, a pinion 81 meshing-thereWithend a rack-8O secured to the rod; and engagingthe' said pinion;

The movcmnts of the rack 84' are controlled by theicalculating box 85 (Fig. 11). The principle which is embodiedinthis calculating mechanism is a very simple triangugitudinal movements i lation principle diagrammatically illustrated on Fig. 12. If the right angled triangle 71/12 is considered'wherein pg isa constant and length ps equal D to V is measured along the side pg and a parallel st, to gr is drawn through the point 8 the following equality-is obtained:

and g) is equal t o i P P9 if x is supposed to indicate'st; this gives Therefore a: is save a constant factor, equal to the product The mechanism itself comprises a carriage 86 which is moved by the milled knob 87 so in a box 73 which can be -raised-or lowered with reference 'to the l casing 72 and rotate as to make theindex 88 mark the required value on the speed scale 89.

Perpendicularly to the direction of the -m0vement of this carriage is disposed a rod 76 which is controlled by the knob 77 and which allows the accurate setting of the back-sight as explained hereinabore. This rod76 which is threaded on part of its length bears-a nut 90 which is adapted to move longitudinally along the rod. This nut is provided with a projectionfil which engages the roove 92 of a lever oscillating rounda point-94' which is the origin of the vector .representing the speeds and which corresponds ;to the.point' p' of the triangle pgniniFig. 12. The distance from point 94 to 'theirod Z6 is; constant. The-point of the leven 93Jn'oiies in front ofla. graduation 95 whereon. aremarked the distances D, this :grad-uation being such as will make-the disthat the distance interferestwieein this arrangement oncerforthe back sight and'once e'anibe seen "for -th'e conectibnflut: to they displacement of-the index'-88.: The'lever 93'is provided on the other hand with a slot 98 disposedalong its fin;ger 99 adapted to pass through bothslots and is secured besides-to -'the;slider loQqvhichcanvslide in the slot 101 provided inthe-bent end of the rack84- It can be seen: that-the finger-99 will be constantly held at thejntersectlon of: the slot 101 andmfjthe slot- 197. ';By means: of the Jslidenit-thus'causes the-rack 84 to ;move as required'proportionateljto What claim is:

'L'Sight-lin for fire-arms-adapted to fire against morablc aerial targets comprising a' constantly've'rt-ical cylindrical casing secured to the firearm, a-cylindrical box disposed inside said casing; means -for rotating and -for vmoving longitudinally said box 'ith reference to the casing, a projection m1 said casing, a directing shaft pivotally ::c cured to said projection and adapted to he directed parallel to the path of the aerial target, a vertical shaft passing through the cylindrical bo.\' connected with the directing shaft, and adapted to move along a radius of the box, a connecting rod linked with last mentioned vertical-shaft and with a point of the (ire arm and aiming means sccured to said connecting rod.

2. Sight line for fire-arms adapted to tire against movable aerial targets comprising a support secured to the tire a'rm a cylindrical casing secured after the manner of a pcndir lum to said-support, a cylindrical box disposed inside said casing,-means for rotating and for moving longitudinally said box with reference to the casing, a PlOjI-ZtitlOfL on said casing a directing shaft pirotally secured to said projection and adapted to be directed parallel to the path of the aerial target, a vertical shaft passing through tlle cylindrical be: conncrltd with the directing shaft, and adapted to more along a radiusotethe box a connecting. rod linked -\\'ith;l a st,mentioned vertical shaft and with a pointof lire arm, aiming. means secured to said co:n- :zectin; rod and a second connecting ro parallel to the first rod secured togthe vertical shaft and to a point of the fire-arm, a:

- 3. Sight-line for firearms-adapted to: dire against moi-able aerial 'targetsgcomprisin n-a support secured .to the [ire a-rm;-a cylirr rical casingsecured after-themanneizot -a pendulum to said support, a cylindrical box -disposedinside said casing imeans for, ro-- tating and for moving.longituelinall ,,said box with referencelothe caSingQa rojection onsaid casing, a directing shafltrpigotall v secured to said projectiom-andfidapted to be directed parallel to the pa th-, ,of the aerial target, a vertical shaft passingfihrongh the cylindri 21 box; eonnected withfihewdi resting shaft, and; adapted to rnoye alonga radius of the box,-a. connectin' rod-linked.

i t h last mentioned vertical shaft and pvzith -a point of the firearm, aiming=means secured to saidco'nnecting'rodmnda secondrepnneeb ing rod parallel to then-first-rodfieq tgddto the vertical tsha-ft" and=-t o a pointzgofgthqffire a rm and means whereby rtheirotatiqn, ofigthe di recting-s'haft; round the Projetiomptoyides fol-the correctiqmdue t -tlIe change .,-i'n the speed. of, tlie za'e'rialjtargetfiighen it; 'doesmot move in a=horizontal=plane.-f i

4'. Sightlinefor.fifiemtmsadapttid'io a against movablezaerial targets comprising a sitpport secured t'o--t-lie :fire-a'rm -a; cylindrical casing secured-after the. manner. sofizia pendulum :to said-support,-a cylindrical box disposed-"inside said easing, means-fox? rotating and for moving longitudinally "said boxwrith reference to' the casing,'afprojection .the box; a connecting-rod linked with-last =nientioncd vertical shaft and with ai pointof the tire arm, niming'meanssecured to said connecting rod'and a-secon'd connecting-rod parallel '(OiliC first rod secured to the .vertical shaft and -'to a pointof the fire-arm, a socket surrounding-the vertical. shaft, 3 rnov-- ahle carriage surrounding sa ine {a second carriage sliding: inside said mogableear riage, means for moving said second carriage proportionately to .the speed of the aerial target, means whereby the said second carriage control those of the first carriage and of the cylindrical box, the first carriage being moreover independently controlled by the rotation of the directing shaft.

5. Sight-line for fire-arms adapted to fire against movable aerial targets comprising a constantly vertical cylindrical casing secured to the fire-arms, a cylindrical box disposed inside said casing, means for rotating and for moving longitudinally said box with reference to the casing, a projection on said casing, a directing shaft pivotally secured to said projection and adapted to be directed parallel to"- the path of the aerial target, a verticalshaftpassing through the cylindrical bo'x connected with the directing shaft,

- and adaptedjto move along a radius of the box, a connecting rod linked with lastmentioned vertical shaft and with an adjustable point of the fire arm and aiming means secured to said connecting rod, means whereby the distance of the vertical shaft to the axis of thevertical casing is proportional to the speedof the target and a part providing simult 'aneously for a vertical movement of the box with-reference to the casing which is adapted to give the back sight correction and fort-he movement of the adjustable connection of the connecting rod along the fire arm, both movements being proportional to thedlstance D.

n. 6, ,S ight;1ine for fire-arms adapted to pr1s1ng a constantly vertical cylindrical casin secured to the fire arm, a cylindrica box disposed inside said casing, means for V rotating and for moving 1onbox with reference to the ,api-ojection on said casing, a directsaid connecting rod, and a calculating mechanism providing for said vertical shaft to move along a radius of the casing and for the distance thereof to the axis of the casing to be proportional to 7. A sight line as claimed in claim 6 wherein the calculating mechanism comprises a carriage the movements of which are proportional to V, a slider adapted to move perpendicularly to the movement of the carriage and the movements of Which are proportional to g, a slotted lever connecting the slider to the zero of a speed scale, a slot provided in the carriage and parallel to the movements of the slider, 21 finger engaging this slot and the slot in the lever whereby it is moved by a distance proporgi l t T? and means whereby the movemove perpendicularly to the movement of' the carriage and the movements of which are proportional to a slotted lever connecting the slider to the zero of a speed scale, a slot provided in the carriage and parallel to the movements of the slider, a finger engaging this slot and the slot in the lever.

whereby it is moved by a distance proportional to and means whereby the movements of the finger are transmitted to the vertical shaft and a part controlling simultaneously the slider and the back sight.

In testimony whereof I afiix my signature.

YVES PAUL GASTON LE PRIEUR. 

